Gilgamesh

Two siblings, Kiyoko and Tatsuya, live in a future reshaped by a terrorist attack known only as "Twin X". In this terrible new world, advanced technology such as computers and radios no longer function and even the very sky has become something terrifyingly alien. With the siblings' mother dead, they are hunted by loan sharks who want recompense for her debt as well as a mysterious Countess who wants them for her own reasons. Even worse, they are also coveted by their father, the terrorist who caused the "Twin X", Gilgamesh!